1
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Pajola M, Tusberti F, Lucchetti A, Barnouin O, Cambioni S, Ernst CM, Dotto E, Daly RT, Poggiali G, Hirabayashi M, Nakano R, Epifani EM, Chabot NL, Della Corte V, Rivkin A, Agrusa H, Zhang Y, Penasa L, Ballouz RL, Ivanovski S, Murdoch N, Rossi A, Robin C, Ieva S, Vincent JB, Ferrari F, Raducan SD, Campo-Bagatin A, Parro L, Benavidez P, Tancredi G, Karatekin Ö, Trigo-Rodriguez JM, Sunshine J, Farnham T, Asphaug E, Deshapriya JDP, Hasselmann PHA, Beccarelli J, Schwartz SR, Abell P, Michel P, Cheng A, Brucato JR, Zinzi A, Amoroso M, Pirrotta S, Impresario G, Bertini I, Capannolo A, Caporali S, Ceresoli M, Cremonese G, Dall'Ora M, Gai I, Casajus LG, Gramigna E, Manghi RL, Lavagna M, Lombardo M, Modenini D, Palumbo P, Perna D, Tortora P, Zannoni M, Zanotti G. Evidence for multi-fragmentation and mass shedding of boulders on rubble-pile binary asteroid system (65803) Didymos. Nat Commun 2024; 15:6205. [PMID: 39080257 PMCID: PMC11289111 DOI: 10.1038/s41467-024-50148-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 07/02/2024] [Indexed: 08/02/2024] Open
Abstract
Asteroids smaller than 10 km are thought to be rubble piles formed from the reaccumulation of fragments produced in the catastrophic disruption of parent bodies. Ground-based observations reveal that some of these asteroids are today binary systems, in which a smaller secondary orbits a larger primary asteroid. However, how these asteroids became binary systems remains unclear. Here, we report the analysis of boulders on the surface of the stony asteroid (65803) Didymos and its moonlet, Dimorphos, from data collected by the NASA DART mission. The size-frequency distribution of boulders larger than 5 m on Dimorphos and larger than 22.8 m on Didymos confirms that both asteroids are piles of fragments produced in the catastrophic disruption of their progenitors. Dimorphos boulders smaller than 5 m have size best-fit by a Weibull distribution, which we attribute to a multi-phase fragmentation process either occurring during coalescence or during surface evolution. The density per km2 of Dimorphos boulders ≥1 m is 2.3x with respect to the one obtained for (101955) Bennu, while it is 3.0x with respect to (162173) Ryugu. Such values increase once Dimorphos boulders ≥5 m are compared with Bennu (3.5x), Ryugu (3.9x) and (25143) Itokawa (5.1x). This is of interest in the context of asteroid studies because it means that contrarily to the single bodies visited so far, binary systems might be affected by subsequential fragmentation processes that largely increase their block density per km2. Direct comparison between the surface distribution and shapes of the boulders on Didymos and Dimorphos suggest that the latter inherited its material from the former. This finding supports the hypothesis that some asteroid binary systems form through the spin up and mass shedding of a fraction of the primary asteroid.
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Affiliation(s)
- M Pajola
- INAF-Astronomical Observatory of Padova, Padova, Italy.
| | - F Tusberti
- INAF-Astronomical Observatory of Padova, Padova, Italy
| | - A Lucchetti
- INAF-Astronomical Observatory of Padova, Padova, Italy
| | - O Barnouin
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - S Cambioni
- Department of Earth, Atmospheric and Planetary Sciences, Massachussets Institute of Technology, Cambridge, MA, USA
| | - C M Ernst
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - E Dotto
- INAF-Osservatorio Astronomico di Roma, Roma, Italy
| | - R T Daly
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - G Poggiali
- INAF-Osservatorio Astrofisico di Arcetri, Firenze, Italy
- LESIA-Observatorie de Paris PSL, Paris, France
| | | | - R Nakano
- Georgia Institute of Technology, Atlanta, GA, USA
- Department of Aerospace Engineering, Auburn University, Auburn, AL, USA
| | | | - N L Chabot
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - V Della Corte
- INAF-Osservatorio Astronomico di Capodimonte, Napoli, Italy
| | - A Rivkin
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - H Agrusa
- Department of Astronomy, University of Maryland, College Park, MD, USA
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
| | - Y Zhang
- Climate & Space Sciences and Engineering, University of Michigan, Hayward, MI, USA
| | - L Penasa
- INAF-Astronomical Observatory of Padova, Padova, Italy
| | - R-L Ballouz
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - S Ivanovski
- INAF-Osservatorio Astronomico di Trieste, Trieste, Italy
| | - N Murdoch
- Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Université de, Toulouse, France
| | - A Rossi
- IFAC-CNR, Sesto Fiorentino, Firenze, Italy
| | - C Robin
- Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Université de, Toulouse, France
| | - S Ieva
- INAF-Osservatorio Astronomico di Roma, Roma, Italy
| | | | - F Ferrari
- Dipartimento di Scienze e Tecnologie Aerospaziali, Politecnico di Milano-Bovisa Campus, Milano, Italy
| | - S D Raducan
- Space Research and Planetary Sciences, Physikalisches Institut, University of Bern, Bern, Switzerland
| | | | - L Parro
- Universidad de Alicante, de Alicante, Spain
- University of Arizona, Tucson, AZ, USA
| | | | - G Tancredi
- Dpto. Astronomia, Facultad Ciencias Igua, Montevideo, Uruguay
| | - Ö Karatekin
- Royal Observatory of Belgium, Uccle, Belgium
| | - J M Trigo-Rodriguez
- Institute of Space Sciences (ICE, CSIC) and Institut d'Estudis Espacials de Catalunya (IEEC), Barcelona, Spain
| | - J Sunshine
- Department of Astronomy, University of Maryland, College Park, MD, USA
| | - T Farnham
- Department of Astronomy, University of Maryland, College Park, MD, USA
| | - E Asphaug
- Planetary Science Institute; University of Arizona, Tucson, AZ, USA
| | | | | | - J Beccarelli
- INAF-Astronomical Observatory of Padova, Padova, Italy
| | - S R Schwartz
- Planetary Science Institute; University of Arizona, Tucson, AZ, USA
| | - P Abell
- NASA Johnson Space Center, Houston, TX, USA
| | - P Michel
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
- Department of Systems Innovation, School of Engineering, The University of Tokyo, Tokyo, Japan
| | - A Cheng
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - J R Brucato
- INAF-Osservatorio Astrofisico di Arcetri, Firenze, Italy
| | - A Zinzi
- Agenzia Spaziale Italiana, Roma, Italy
- Space Science Data Center-ASI, Roma, Italy
| | - M Amoroso
- Agenzia Spaziale Italiana, Roma, Italy
| | | | | | - I Bertini
- Dipartimento di Scienze & Tecnologie, Università degli Studi di Napoli "Parthenope", Napoli, Italy
| | - A Capannolo
- Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Université de, Toulouse, France
| | - S Caporali
- INAF-Osservatorio Astrofisico di Arcetri, Firenze, Italy
| | - M Ceresoli
- Dipartimento di Scienze e Tecnologie Aerospaziali, Politecnico di Milano-Bovisa Campus, Milano, Italy
| | - G Cremonese
- INAF-Astronomical Observatory of Padova, Padova, Italy
| | - M Dall'Ora
- INAF-Osservatorio Astronomico di Capodimonte, Napoli, Italy
| | - I Gai
- Dipartimento di Ingegneria Industriale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
- Centro Interdipartimentale di Ricerca Industriale Aerospaziale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
| | - L Gomez Casajus
- Dipartimento di Ingegneria Industriale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
- Centro Interdipartimentale di Ricerca Industriale Aerospaziale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
| | - E Gramigna
- Dipartimento di Ingegneria Industriale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
- Centro Interdipartimentale di Ricerca Industriale Aerospaziale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
| | - R Lasagni Manghi
- Dipartimento di Ingegneria Industriale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
- Centro Interdipartimentale di Ricerca Industriale Aerospaziale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
| | - M Lavagna
- Dipartimento di Scienze e Tecnologie Aerospaziali, Politecnico di Milano-Bovisa Campus, Milano, Italy
| | - M Lombardo
- Dipartimento di Ingegneria Industriale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
- Centro Interdipartimentale di Ricerca Industriale Aerospaziale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
| | - D Modenini
- Dipartimento di Ingegneria Industriale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
- Centro Interdipartimentale di Ricerca Industriale Aerospaziale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
| | - P Palumbo
- INAF-Istituto di Astrofisica e Planetologia Spaziali, Roma, Italy
| | - D Perna
- INAF-Osservatorio Astronomico di Roma, Roma, Italy
| | - P Tortora
- Dipartimento di Ingegneria Industriale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
- Centro Interdipartimentale di Ricerca Industriale Aerospaziale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
| | - M Zannoni
- Dipartimento di Ingegneria Industriale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
- Centro Interdipartimentale di Ricerca Industriale Aerospaziale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
| | - G Zanotti
- Dipartimento di Scienze e Tecnologie Aerospaziali, Politecnico di Milano-Bovisa Campus, Milano, Italy
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2
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Lucchetti A, Cambioni S, Nakano R, Barnouin OS, Pajola M, Penasa L, Tusberti F, Ramesh KT, Dotto E, Ernst CM, Daly RT, Mazzotta Epifani E, Hirabayashi M, Parro L, Poggiali G, Campo Bagatin A, Ballouz RL, Chabot NL, Michel P, Murdoch N, Vincent JB, Karatekin Ö, Rivkin AS, Sunshine JM, Kohout T, Deshapriya JDP, Hasselmann PHA, Ieva S, Beccarelli J, Ivanovski SL, Rossi A, Ferrari F, Rossi C, Raducan SD, Steckloff J, Schwartz S, Brucato JR, Dall'Ora M, Zinzi A, Cheng AF, Amoroso M, Bertini I, Capannolo A, Caporali S, Ceresoli M, Cremonese G, Della Corte V, Gai I, Gomez Casajus L, Gramigna E, Impresario G, Lasagni Manghi R, Lavagna M, Lombardo M, Modenini D, Palumbo P, Perna D, Pirrotta S, Tortora P, Zannoni M, Zanotti G. Fast boulder fracturing by thermal fatigue detected on stony asteroids. Nat Commun 2024; 15:6206. [PMID: 39080275 PMCID: PMC11289370 DOI: 10.1038/s41467-024-50145-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 05/09/2024] [Indexed: 08/02/2024] Open
Abstract
Spacecraft observations revealed that rocks on carbonaceous asteroids, which constitute the most numerous class by composition, can develop millimeter-to-meter-scale fractures due to thermal stresses. However, signatures of this process on the second-most populous group of asteroids, the S-complex, have been poorly constrained. Here, we report observations of boulders' fractures on Dimorphos, which is the moonlet of the S-complex asteroid (65803) Didymos, the target of NASA's Double Asteroid Redirection Test (DART) planetary defense mission. We show that the size-frequency distribution and orientation of the mapped fractures are consistent with formation through thermal fatigue. The fractures' preferential orientation supports that these have originated in situ on Dimorphos boulders and not on Didymos boulders later transferred to Dimorphos. Based on our model of the fracture propagation, we propose that thermal fatigue on rocks exposed on the surface of S-type asteroids can form shallow, horizontally propagating fractures in much shorter timescales (100 kyr) than in the direction normal to the boulder surface (order of Myrs). The presence of boulder fields affected by thermal fracturing on near-Earth asteroid surfaces may contribute to an enhancement in the ejected mass and momentum from kinetic impactors when deflecting asteroids.
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Affiliation(s)
- A Lucchetti
- INAF-Astronomical Observatory of Padova, Vic. Osservatorio 5, 35122, Padova, Italy.
| | - S Cambioni
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - R Nakano
- Daniel Guggenheim School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
- Department of Aerospace Engineering, Auburn University, Auburn, AL, 36849, USA
| | - O S Barnouin
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, 20723, USA
| | - M Pajola
- INAF-Astronomical Observatory of Padova, Vic. Osservatorio 5, 35122, Padova, Italy
| | - L Penasa
- INAF-Astronomical Observatory of Padova, Vic. Osservatorio 5, 35122, Padova, Italy
| | - F Tusberti
- INAF-Astronomical Observatory of Padova, Vic. Osservatorio 5, 35122, Padova, Italy
| | - K T Ramesh
- Johns Hopkins University, Baltimore, MD, USA
| | - E Dotto
- INAF-Osservatorio Astronomico di Roma, Monte Porzio Catone, Roma, Italy
| | - C M Ernst
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, 20723, USA
| | - R T Daly
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, 20723, USA
| | | | - M Hirabayashi
- Daniel Guggenheim School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
- Department of Aerospace Engineering, Auburn University, Auburn, AL, 36849, USA
| | - L Parro
- IUFACyT. Universidad de Alicante, Alicante, Spain
- University of Arizona, Tucson, AZ, USA
- Universidad Complutense, Madrid, Spain
| | - G Poggiali
- INAF-Osservatorio Astrofisico di Arcetri, Firenze, Italy
- LESIA-Observatorie de Paris PSL, Paris, France
| | - A Campo Bagatin
- IUFACyT. Universidad de Alicante, Alicante, Spain
- Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Universidad de Alicante, Alicante, Spain
| | - R-L Ballouz
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, 20723, USA
| | - N L Chabot
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, 20723, USA
| | - P Michel
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
- School of Engineering, Department of Systems Innovation, The University of Tokyo, Tokyo, Japan
| | - N Murdoch
- Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Université de Toulouse, Toulouse, France
| | - J B Vincent
- DLR Institute of Planetary Research, Berlin, Germany
| | - Ö Karatekin
- Royal Observatory of Belgium, Uccle, Belgium
| | - A S Rivkin
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, 20723, USA
| | - J M Sunshine
- Departments of Astronomy and Geology, University of Maryland, College Park, MD, USA
| | - T Kohout
- University of Helsinki, Helsinki, Finland
- Institute of Geology of the Czech Academy of Sciences, Prague, Czech Republic
| | - J D P Deshapriya
- INAF-Osservatorio Astronomico di Roma, Monte Porzio Catone, Roma, Italy
| | - P H A Hasselmann
- INAF-Osservatorio Astronomico di Roma, Monte Porzio Catone, Roma, Italy
| | - S Ieva
- INAF-Osservatorio Astronomico di Roma, Monte Porzio Catone, Roma, Italy
| | - J Beccarelli
- INAF-Astronomical Observatory of Padova, Vic. Osservatorio 5, 35122, Padova, Italy
| | - S L Ivanovski
- INAF-Osservatorio Astronomico di Trieste, Trieste, Italy
| | - A Rossi
- IFAC-CNR, Sesto Fiorentino, Firenze, Italy
| | - F Ferrari
- Dipartimento di Scienze e Tecnologie Aerospaziali, Politecnico di Milano - Bovisa Campus, Milano, Italy
| | - C Rossi
- INAF-Astronomical Observatory of Padova, Vic. Osservatorio 5, 35122, Padova, Italy
| | - S D Raducan
- Space Research and Planetary Sciences, Physikalisches Institut, University of Bern, Bern, Switzerland
| | - J Steckloff
- Planetary Science Institute, Tucson, AZ, USA
| | - S Schwartz
- Planetary Science Institute, Tucson, AZ, USA
| | - J R Brucato
- INAF-Osservatorio Astrofisico di Arcetri, Firenze, Italy
| | - M Dall'Ora
- INAF-Osservatorio Astronomico di Capodimonte, Napoli, Italy
| | - A Zinzi
- Space Science Data Center - ASI, Roma, Italy
| | - A F Cheng
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, 20723, USA
| | - M Amoroso
- Agenzia Spaziale Italiana, Roma, Italy
| | - I Bertini
- Dipartimento di Scienze & Tecnologie, Università degli Studi di Napoli "Parthenope", Centro Direzionale, Napoli, Italy
| | - A Capannolo
- Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Université de Toulouse, Toulouse, France
| | - S Caporali
- INAF-Osservatorio Astrofisico di Arcetri, Firenze, Italy
| | - M Ceresoli
- Dipartimento di Scienze e Tecnologie Aerospaziali, Politecnico di Milano - Bovisa Campus, Milano, Italy
| | - G Cremonese
- INAF-Astronomical Observatory of Padova, Vic. Osservatorio 5, 35122, Padova, Italy
| | - V Della Corte
- INAF-Osservatorio Astronomico di Capodimonte, Napoli, Italy
| | - I Gai
- Dipartimento di Ingegneria Industriale, Alma Mater Studiorum - Università di Bologna, Forlì, Italy
| | - L Gomez Casajus
- Centro Interdipartimentale di Ricerca Industriale Aerospaziale, Alma Mater Studiorum, Università di Bologna, Forlì, Italy
| | - E Gramigna
- Dipartimento di Ingegneria Industriale, Alma Mater Studiorum - Università di Bologna, Forlì, Italy
| | | | - R Lasagni Manghi
- Dipartimento di Ingegneria Industriale, Alma Mater Studiorum - Università di Bologna, Forlì, Italy
| | - M Lavagna
- Dipartimento di Scienze e Tecnologie Aerospaziali, Politecnico di Milano - Bovisa Campus, Milano, Italy
| | - M Lombardo
- Dipartimento di Ingegneria Industriale, Alma Mater Studiorum - Università di Bologna, Forlì, Italy
| | - D Modenini
- Dipartimento di Ingegneria Industriale, Alma Mater Studiorum - Università di Bologna, Forlì, Italy
- Centro Interdipartimentale di Ricerca Industriale Aerospaziale, Alma Mater Studiorum, Università di Bologna, Forlì, Italy
| | - P Palumbo
- INAF-Istituto di Astrofisica e Planetologia Spaziali, Roma, Italy
| | - D Perna
- INAF-Osservatorio Astronomico di Roma, Monte Porzio Catone, Roma, Italy
| | | | - P Tortora
- Dipartimento di Ingegneria Industriale, Alma Mater Studiorum - Università di Bologna, Forlì, Italy
- Centro Interdipartimentale di Ricerca Industriale Aerospaziale, Alma Mater Studiorum, Università di Bologna, Forlì, Italy
| | - M Zannoni
- Dipartimento di Ingegneria Industriale, Alma Mater Studiorum - Università di Bologna, Forlì, Italy
- Centro Interdipartimentale di Ricerca Industriale Aerospaziale, Alma Mater Studiorum, Università di Bologna, Forlì, Italy
| | - G Zanotti
- Dipartimento di Scienze e Tecnologie Aerospaziali, Politecnico di Milano - Bovisa Campus, Milano, Italy
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3
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Zhang Y, Michel P, Barnouin OS, Roberts JH, Daly MG, Ballouz RL, Walsh KJ, Richardson DC, Hartzell CM, Lauretta DS. Inferring interiors and structural history of top-shaped asteroids from external properties of asteroid (101955) Bennu. Nat Commun 2022; 13:4589. [PMID: 35933392 PMCID: PMC9357032 DOI: 10.1038/s41467-022-32288-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 07/20/2022] [Indexed: 11/30/2022] Open
Abstract
Asteroid interiors play a key role in our understanding of asteroid formation and evolution. As no direct interior probing has been done yet, characterisation of asteroids’ interiors relies on interpretations of external properties. Here we show, by numerical simulations, that the top-shaped rubble-pile asteroid (101955) Bennu’s geophysical response to spinup is highly sensitive to its material strength. This allows us to infer Bennu’s interior properties and provide general implications for top-shaped rubble piles’ structural evolution. We find that low-cohesion (≲0.78 Pa at surface and ≲1.3 Pa inside) and low-friction (friction angle ≲ 35∘) structures with several high-cohesion internal zones can consistently account for all the known geophysical characteristics of Bennu and explain the absence of moons. Furthermore, we reveal the underlying mechanisms that lead to different failure behaviours and identify the reconfiguration pathways of top-shaped asteroids as functions of their structural properties that either facilitate or prevent the formation of moons. Asteroid interiors are key to understand their formation and evolution. Here, the authors show that numerically simulated low-cohesion and low-friction structures with several high-cohesion internal zones can explain asteroid Bennu’s geophysical characteristics and the absence of the moons.
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Affiliation(s)
- Yun Zhang
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France. .,Department of Aerospace Engineering, University of Maryland, College Park, MD, USA.
| | - Patrick Michel
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
| | - Olivier S Barnouin
- The Johns Hopkins University, Applied Physics Laboratory, Laurel, MD, USA
| | - James H Roberts
- The Johns Hopkins University, Applied Physics Laboratory, Laurel, MD, USA
| | - Michael G Daly
- The Centre for Research in Earth and Space Science, York University, Toronto, ON, Canada
| | - Ronald-L Ballouz
- The Johns Hopkins University, Applied Physics Laboratory, Laurel, MD, USA.,Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | | | | | - Christine M Hartzell
- Department of Aerospace Engineering, University of Maryland, College Park, MD, USA
| | - Dante S Lauretta
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
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4
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Walsh KJ, Ballouz RL, Jawin ER, Avdellidou C, Barnouin OS, Bennett CA, Bierhaus EB, Bos BJ, Cambioni S, Connolly HC, Delbo M, DellaGiustina DN, DeMartini J, Emery JP, Golish DR, Haas PC, Hergenrother CW, Ma H, Michel P, Nolan MC, Olds R, Rozitis B, Richardson DC, Rizk B, Ryan AJ, Sánchez P, Scheeres DJ, Schwartz SR, Selznick SH, Zhang Y, Lauretta DS. Near-zero cohesion and loose packing of Bennu's near subsurface revealed by spacecraft contact. SCIENCE ADVANCES 2022; 8:eabm6229. [PMID: 35857450 PMCID: PMC9262326 DOI: 10.1126/sciadv.abm6229] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
When the OSIRIS-REx spacecraft pressed its sample collection mechanism into the surface of Bennu, it provided a direct test of the poorly understood near-subsurface physical properties of rubble-pile asteroids, which consist of rock fragments at rest in microgravity. Here, we find that the forces measured by the spacecraft are best modeled as a granular bed with near-zero cohesion that is half as dense as the bulk asteroid. The low gravity of a small rubble-pile asteroid such as Bennu effectively weakens its near subsurface by not compressing the upper layers, thereby minimizing the influence of interparticle cohesion on surface geology. The underdensity and weak near subsurface should be global properties of Bennu and not localized to the contact point.
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Affiliation(s)
- Kevin J. Walsh
- Southwest Research Institute, Boulder, CO, USA
- Corresponding author.
| | - Ronald-Louis Ballouz
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - Erica R. Jawin
- National Air and Space Museum, Smithsonian Institution, Washington, DC, USA
| | - Chrysa Avdellidou
- Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Nice, France
| | | | - Carina A. Bennett
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | | | - Brent J. Bos
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - Saverio Cambioni
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Harold C. Connolly
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
- Department of Geology, Rowan University, Glassboro, NJ, USA
| | - Marco Delbo
- Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Nice, France
| | | | - Joseph DeMartini
- Department of Astronomy, University of Maryland, College Park, MD, USA
| | - Joshua P. Emery
- Department of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, AZ, USA
| | - Dathon R. Golish
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | | | | | - Huikang Ma
- Lockheed Martin Space, Littleton, CO, USA
| | - Patrick Michel
- Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Nice, France
| | - Michael C. Nolan
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - Ryan Olds
- Lockheed Martin Space, Littleton, CO, USA
| | - Benjamin Rozitis
- School of Physical Sciences, The Open University, Milton Keynes, UK
| | | | - Bashar Rizk
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - Andrew J. Ryan
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - Paul Sánchez
- Colorado Center for Astrodynamics Research, University of Colorado Boulder, Boulder, CO, USA
| | - Daniel J. Scheeres
- Colorado Center for Astrodynamics Research, University of Colorado Boulder, Boulder, CO, USA
- Smead Aerospace Engineering Sciences Department, University of Colorado Boulder, Boulder, CO, USA
| | - Stephen R. Schwartz
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
- Planetary Science Institute, Tucson, AZ, USA
| | | | - Yun Zhang
- Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Nice, France
| | - Dante S. Lauretta
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
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Walsh KJ, Bierhaus EB, Lauretta DS, Nolan MC, Ballouz RL, Bennett CA, Jawin ER, Barnouin OS, Berry K, Burke KN, Brodbeck B, Burns R, Clark BC, Clark BE, Cambioni S, Connolly HC, Daly MG, Delbo M, DellaGiustina DN, Dworkin JP, Enos HL, Emery JP, Gay P, Golish DR, Hamilton VE, Hoover R, Lujan M, McCoy T, Mink RG, Moreau MC, Nolau J, Padilla J, Pajola M, Polit AT, Robbins SJ, Ryan AJ, Selznick SH, Stewart S, Wolner CWV. Assessing the Sampleability of Bennu's Surface for the OSIRIS-REx Asteroid Sample Return Mission. SPACE SCIENCE REVIEWS 2022; 218:20. [PMID: 35528719 PMCID: PMC9018658 DOI: 10.1007/s11214-022-00887-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/28/2022] [Indexed: 05/18/2023]
Abstract
NASA's first asteroid sample return mission, OSIRIS-REx, collected a sample from the surface of near-Earth asteroid Bennu in October 2020 and will deliver it to Earth in September 2023. Selecting a sample collection site on Bennu's surface was challenging due to the surprising lack of large ponded deposits of regolith particles exclusively fine enough ( ≤ 2 cm diameter) to be ingested by the spacecraft's Touch-and-Go Sample Acquisition Mechanism (TAGSAM). Here we describe the Sampleability Map of Bennu, which was constructed to aid in the selection of candidate sampling sites and to estimate the probability of collecting sufficient sample. "Sampleability" is a numeric score that expresses the compatibility of a given area's surface properties with the sampling mechanism. The algorithm that determines sampleability is a best fit functional form to an extensive suite of laboratory testing outcomes tracking the TAGSAM performance as a function of four observable properties of the target asteroid. The algorithm and testing were designed to measure and subsequently predict TAGSAM collection amounts as a function of the minimum particle size, maximum particle size, particle size frequency distribution, and the tilt of the TAGSAM head off the surface. The sampleability algorithm operated at two general scales, consistent with the resolution and coverage of data collected during the mission. The first scale was global and evaluated nearly the full surface. Due to Bennu's unexpected boulder coverage and lack of ponded regolith deposits, the global sampleability efforts relied heavily on additional strategies to find and characterize regions of interest based on quantifying and avoiding areas heavily covered by material too large to be collected. The second scale was site-specific and used higher-resolution data to predict collected mass at a given contact location. The rigorous sampleability assessments gave the mission confidence to select the best possible sample collection site and directly enabled successful collection of hundreds of grams of material.
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Affiliation(s)
| | | | - Dante S. Lauretta
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ USA
| | - Michael C. Nolan
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ USA
| | | | - Carina A. Bennett
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ USA
| | - Erica R. Jawin
- National Air and Space Museum, Smithsonian Institution, Washington, DC USA
| | | | - Kevin Berry
- NASA Goddard Spaceflight Center, Greenbelt, MD USA
| | - Keara N. Burke
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ USA
| | - Bella Brodbeck
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ USA
| | - Rich Burns
- NASA Goddard Spaceflight Center, Greenbelt, MD USA
| | | | - Beth E. Clark
- Department of Physics and Astronomy, Ithaca College, Ithaca, NY USA
| | - Saverio Cambioni
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA USA
| | - Harold C. Connolly
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ USA
- Department of Geology, Rowan University, Glassboro, NJ USA
| | - Michael G. Daly
- Centre for Research in Earth and Space Science, York University, Toronto, CA USA
| | - Marco Delbo
- CNRS-Observatoire de la Côte d’Azur, Nice, France
| | | | | | - Heather L. Enos
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ USA
| | | | - Pamela Gay
- University of Central Florida, Orlando, FL USA
| | - Dathon R. Golish
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ USA
| | | | | | - Michael Lujan
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ USA
| | - Timothy McCoy
- Smithsonian Institution National Museum of Natural History, Washington, DC USA
| | | | | | | | - Jacob Padilla
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ USA
| | | | - Anjani T. Polit
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ USA
| | | | - Andrew J. Ryan
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ USA
| | | | - Stephanie Stewart
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ USA
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